In the related art, there is a magnet embedded rotor including a notch portion that is located on an outer circumference between salient poles adjacent to each other; a bridge that is located between the notch portion and a nonmagnetic portion; and a first protrusion that protrudes outward from the center of the notch portion, in which a radius of each of the salient poles gradually decreases from the center of the salient pole toward the notch portion, and a radius of the first protrusion is the same as a radius of the center of each of the salient pole (refer to JP-A-2012-120326).
In the magnet embedded rotor disclosed in JP-A-2012-120326, as illustrated in FIG. 14A, notch portions 217a and 216b, and a first protrusion 218a protruding outward from the center between the notch portion 217a and the notch portion 216b are formed on an outer circumference between salient poles 211 and 212 of a rotor 210 adjacent to each other. Consequently, an induced voltage waveform generated from permanent magnets 213 and 214 becomes similar to a sine wave since harmonic components are reduced. Therefore, cogging torque is reduced, and thus vibration or noise of an electric motor is reduced. However, in FIG. 14B illustrating an induced voltage waveform when the rotor illustrated in FIG. 14A rotates, two horns appear around each of a peak and a bottom. Consequently, the induced voltage waveform becomes similar to a sine wave, but harmonic components of an induced voltage or cogging torque is not sufficiently reduced and thus still remains, and vibration or noise of the electric motor is required to be further reduced.